Japanese researchers have successfully used induced pluripotent stem (iPS) cells in humans. Published in The New England Journal of Medicine, their paper details the use of iPS cells to treat age-related macular degeneration (AMD), a very common eye disease in older people. The stem cells did not cure the AMD, but it slowed the disease and prevented it from becoming more severe.
Stem cells are cells that have not yet differentiated into specialized functions. Induced pluripotent stem cells are a type of stem cell that can be derived from adult cells. Instead of having to extract stem cells embryos, scientist can now reprogram normal adult cells in the lab to produce large quantities of stem cells that could be used in treatments.
The therapeutic potential of stem cells has been researched for years, but the paper published by Michiko Mandai, Masayo Takahashi, and numerous other researchers in Japan, is the first to prove stem cell treatment in humans is not only safe but effective.
“Clinical work is progressing much more quickly than I expected,” commented Shinya Yamanaka, an M.D., Ph.D. at Kyoto University also involved with the research.
The researchers attempted to treat AMD in two patients. The current treatments to correct AMD do not fix damage in the retinal pigment epithelium (RPE), a layer of cells that support the light receptors and blood vessels of the eye. Surgeries can be done to further improve the vision of those suffering from AMD, but the unrepaired damage to the RPE limits the amount of recovery possible.
Using iPS cells, the researchers successfully implanted RPE cells, developed in a lab, into a human eye. By directly attempting to fix damage to the RPE cells, they were able to halt progression of AMD. In one patient, a 77 year-old Japanese women suffering from AMD, they were able to use her skin cells to produce RPE cells that were implanted into her eye. Immediately after surgery, she reported that her vision seemed to be brighter.
Unfortunately, the operation on the second patient, a 68 year-old Japanese man, was cancelled because of unexpected mutations in the iPS cells that were being used to treat his AMD.
“These changes do not directly induce cancer, but we wanted to make safety the first priority,” explained Yamanaka.
These findings are incredibly significant. They mark a milestone in the use of stem cells in regenerative medicine. Although the patients were not cured, the effectiveness of the iPS cells in preventing further eye degeneration is promising. Researchers will likely try to use iPS stem cells in other parts of the body to manage other diseases.
Yamanaka’s colleagues at Kyoto University expect to begin human trials using iPS cells to treat Parkinson’s disease within the next two years.
Source: Mandai M, Watanabe A, Kurimoto Y, et al. Autologous Induced Stem-Cell-Derived Retinal Cells for Macular Degeneration. N Engl J Med. 2017;376(11):1038-1046.